Summary
The Duri field in Sumatra, Indonesia, shown in Fig. 1 and operated by Chevron Pacific Indonesia (CPI), is one of the largest onshore steamflood operations in the world. Producing heavy oil (approximately 25°API) from an essentially unconsolidated reservoir with a depth that ranges from 300 to 700 ft using steam injection at 300 to 400°F poses a unique challenge in designing an effective, yet economic, completion. One of the biggest problems associated with the production of the crude oil in this environment is the production of massive amounts of solids. In addition to the cost of the recompletions, problems associated with disposing of this amount of sand—and the effect the produced solids have on the facilities, such as stabilization of emulsions—are a large cost to operations.
A program was initiated in 2002 to evaluate the effectiveness of the completions in the Duri field. This effort involved evaluated field data, such as the frequency and type of workovers, the amount and size of produced solids, the nature and number of failed liners, and the frequency of stuck sucker-rod pumps, to understand the efficiency of the sand-control completions better. Local sand-control gravel used in the completions was evaluated for steam dissolution and adherence to American Petroleum Institute (API) gravel-pack-sand standards. An audit of the primary sand-control-screen manufacturer was also conducted to evaluate the quality of the sand-control screens used in the completions. In addition, on-site inspections of the operational aspects of the completions were completed. The results of the program showed that the completion designs and sand-control screens were up to industry standards. However, several operational aspects were identified as opportunities for improvement. The results of the program are presented, and items for improvement of the completion for thermal wells in the Duri field are discussed in this paper.
